I have an Nortel Opt11,I task to add a DN to four 3903 telephone sets for a new help desk number.I printed out the unused Dn's found a number place on the 3903's sets.The problem occurs when a caller calls the number.The CID kicks in like it should an give the external number, I need a distinctive ring for the new help desk number or for the number to display Help Desk an not the callers number.Suggestions welcome!!